Story highlights

Police say he and wife Amanda Miller killed two police officers and a third man in Las Vegas

Jerad and Amanda declared a "revolution" was happening, authorities say

Jerad Miller filled his Facebook profile with anti-government rants and warned he was about to make a sacrifice. Amanda Miller posted cute photos about cats -- and a picture of a coffee table built to hide rifles.

Witnesses said the husband and wife shouted about revolution and left a "Don't Tread on Me" flag and a Nazi swastika behind at the scene of Sunday's shooting.

Then Amanda Miller shot her husband dead and killed herself as police closed in, authorities said. Investigators said they're looking at the Millers' social media footprint, interviewing acquaintances and looking at a note pinned to one of the victims as they work to unravel what might have led the pair to ambush police eating lunch at a pizza restaurant, then gun down a shopper at a Walmart across the street.

One possible reason? "They equate government and law enforcement ... with Nazis," Second Assistant Sheriff Kevin McMahill told reporters Monday. "In other words, they believe that law enforcement is the oppressor."

'Dawn of a new day'

Photos: Shootings in Las Vegas 8 photos

Photos: Shootings in Las Vegas8 photos

Shootings in Las Vegas – Police and firefighters on the scene of the shooting at a Las Vegas Walmart, on Sunday, June 8. Two gunmen shot and killed two police officers eating lunch and then killed a third person at the Walmart. The gunmen then killed themselves.

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On June 7, a day before the shooting, a Facebook post from Jerad Miller suggested something was brewing: "The dawn of a new day. May all of our coming sacrifices be worth it."

"People are awakening," said a post that appeared June 5.

On June 2, there was a long rant: "We can hope for peace. We must, however, prepare for war. We face an enemy that is not only well funded, but who believe they fight for freedom and justice. Those of us who know the truth and dare speak it, know that the enemy we face are indeed our brothers. ..."

"To stop this oppression, I fear, can ... only be accomplished with bloodshed," the post says. The writer casts blame on "enemies," but doesn't specify who the enemies are.

Other posts on the page decry the federal government, gun restrictions and taxation.

In face-to-face conversations, it was common to hear Jerad Miller railing against the government, neighbor Kelly Fielder said.

"He was pretty much always talking about how much the government's changed the United States of America," she said. "I thought he was talking smack. To my eyes, they were generally good people at the time. I didn't think they had the guts to go out and really hurt someone."

Court records describe Jerad Miller's past run-ins with the law, including drug charges. In 2007, he pleaded guilty to a felony criminal recklessness charge and was sentenced to a diversion program. In 2011, he pleaded guilty to a felony charge of dealing marijuana and was sentenced to two year's probation and drug counseling.

He was arrested and charged with battery in 2009. A jury acquitted him later that year.

Couple moved to Las Vegas in January

The Millers moved from Indiana to Las Vegas in January, according to Amanda Miller's Facebook page.

She posted two videos of them driving: one that showed the road ahead and another of her at the wheel.

Her Facebook profile also shows pictures of a protest last year in Lafayette, Indiana.

The "Million Mask March" protest's Facebook page describes the November 2013 event as "a march against billionaires who own banks and corporations who corrupt politicians who enslave the people and injustice."

Another picture on her Facebook page in late April shows her and Jerad in costume: He is dressed as the Joker from "Batman" holding up a Joker playing card.

Koch also told the CNN affiliate that Jerad Miller occasionally dressed as Slenderman, a fictional horror character that recently became widely known after two 12-year-old girls were accused of stabbing another 12-year-old girl in Wisconsin. Police said one of the girls told investigators they acted to please Slenderman.

Koch said the Millers told her they were planning an attack. But she discounted them, believing, she said, that they were "crazy."

Neighbor: 'He said the revolution's begun'

Fielder said she saw the couple, who had been living with her for a couple weeks before the shooting, leave with weapons early Sunday morning.

"He said the revolution's begun. I gotta do what I gotta do," she told CNN.

Amanda Miller hugged her, and said "when I die, I'll come back and see you again."

The husband and wife were carrying guns and ammunition, she said.

"They said they were going underground," Fielder said. "They were using it for protection."

The neighbor, who described Amanda Miller as her best friend, said she didn't think they'd take things so far, but now wishes she'd spoken out sooner.

"I got five deaths on my shoulders," she said. "I should have called the cops. ... I'm so, so, so sorry, to everyone."

Connection to Cliven Bundy?

Neighbors at the Las Vegas apartment complex where the couple lived told The Las Vegas Sun they had heard the Millers talk about their support of Nevada rancher Cliven Bundy. One neighbor said Jerad Miller had talked about being at the April armed standoff between Bundy and federal authorities, who began to round up the rancher's cattle after he refused to vacate federally owned land. Hundreds of people, many toting weapons, joined Bundy during the standoff.

Bundy said Monday that he was aware of reports that Jerad Miller was part of the movement that supported him, but said he wasn't aware of Miller.

"Probably 4,000 people came by, and I knew few of them personally," he told CNN's Dan Simon.

His son, Ammon Bundy, said that "state militia members" told him the Millers had been at the ranch, but were asked by a militia member to leave because of "their radical beliefs."

"They didn't align with the reason the protesters were there at the Bundy ranch," he said.

Based on their social media profiles and what investigators have revealed so far, there are no signs the couple was part of a particular group, said Mark Potok, a senior fellow at the Southern Poverty Law Center who studies hate groups and extremism. But they did seem to support the so-called Patriot movement, which decries the federal government and what supporters call the "New World Order."

The couple's support of Bundy, Potok said, could be key.

For many in the Patriot movement, he said, the standoff at Bundy's ranch was a major victory.

"Tens, perhaps hundreds of thousands or more saw what happened at the Bundy ranch as a huge victory against the federal government and perhaps an opening shot at the war that they all wished for and waited for with the government," Potok told CNN's "The Situation Room." "I think it's entirely possible that the Millers, in fact, saw the Bundy standoff as very important, and it may have pushed them over the edge."

A local news crew interview surfaced online Monday, showing Jerad Miller talking about the standoff at the ranch.

"I feel sorry for any federal agents that want to come in here and try to push us around or anything like that," he told NBC at the time. "I really don't want violence toward them, but if they're going to come bring violence to us, well, if that's the language they want to speak, we'll learn it."